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POSeparation of interface from implementation in an inheritance hierarchy (C++ newbie)
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  1. POSeparation of interface from implementation in an inheritance hierarchy (C++ newbie)
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    copied!<p>I am trying to figure out how to arrange some classes. This is what I've got so far ...</p> <p>The top of the inheritance hierarchy is (naturally) T:</p> <pre><code>(T.h) namespace foo { class T { public: virtual void method1(std::string a_parameter) = 0; virtual void method2() = 0; }; } </code></pre> <p>I have two sub-classes of T with some additional methods - here are the header files:</p> <pre><code>(A.h) namespace foo { class A : public T { public: virtual ~A() {}; virtual void method3() = 0; //and a factory function static A* gimmeAnAyy(); }; } (B.h) namespace foo { class B : public T { public: virtual ~B() {}; virtual void method4() = 0; //and a factory function static B* gimmeABee(); }; } </code></pre> <p>The implementation classes are in the respective .cpp files:</p> <pre><code>(A.cpp) namespace foo { class AImpl : public A { public: A(std::string member_data) : m_member_data(member_data) {}; ~A() {}; void method3() { //something really important, can't think of it right now ;-) }; private: std::string m_member_data; }; A* A::gimmeAnAyy() { return new AImpl("this is an impl of A"); }; } (B.cpp) namespace foo { class BImpl : public B { public: B(std::string other_data) : m_other_data(other_data) {}; ~B() {}; void method4() { //something really important, can't think of it right now ;-) }; private: std::string m_other_data; }; B* B::gimmeABee() { return new BImpl("this is an imll of B"); }; } </code></pre> <p>Now the compiler complains - rightly so - about the virtual functions method1() and method2() that I haven't implemented in AImpl and BImpl.</p> <p>What I want is a TImpl class that both AImpl and BImpl can inherit from so that I don't have to implement method1() and method2() in two different .cpp files.</p> <p>Is it possible? Am I out to lunch? Am I asking too many rhetorical questions for a StackExchange post?</p> <h2>Thanks in advance,</h2> <p>Mike</p>
 

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